We experienced three cases of acute gangrenous cholecystitis following a lower gastrointestinal operation. Case 1: A 76-year-old man developed acute gangrenous cholecystitis after left hemicolectomy for a cancer of the descending colon. Case 2: A 51-year-old man had intractable fistula due to perforation of the small intestine after appendectomy for acute appendicitis, and then developed this disease during a long fasting period. Case 3: A 77-year-old man manifested this disease 5 days after sigmoidectomy for perforation of diverticulum in the sigmoid colon. In all 3 cases laparotomy was carried out within several days after the onset and acalculous gangrenous gallbladder was confirmed. It is supposed that fasting due to lower intestinal operation and following initiation of ingestion can be a probable trigger for this disease.